Underneath the 52-square-mile surface area of Sarasota Bay’s expansive range are seagrass meadows currently increasing in size, in health, and in biodiversity despite a population boom that started a hundred years ago and has yet to slow.
Decades of efforts to restore the bay’s deteriorating water quality met with fits and starts, but mostly failure.
Sea grass meadows, the “canary in the coal mine” for a lagoon-like ecosystem along Florida’s Gulf Coast, have been disappearing as the water quality worsened, blocking out the sun the grasses need to grow and allowing algae that thrive on pollution to envelop the grasses and strangle them. Boaters drove their engines through the shallows, collectively ripping out acre after acre of sea grass one prop scar at a time.
Seagrasses provide critical habitat for marine life such as fish, crabs, shrimp, manatees, and sea turtles while also stabilizing shorelines and improving water clarity. They even play a role in mitigating climate change by storing carbon within their root systems.
However, the benefits are easily undone when water quality deteriorates due to nutrient pollution and the damage from boat propellers.
It’s happening all around Florida, in few places worse than the Indian River Lagoon, which runs up the state’s east coast from Palm Beach County to north of Cape Canaveral, where entire sections are devoid of sea grasses — and fish, and manatees, and anglers — due to pollution running into the bay from massive, uncontrolled development along the shoreline.
In Sarasota Bay, stalwarts like Mote Marine Laboratory and Aquarium, the Sarasota Bay Estuary Program, and many other groups worked with water managers and municipal leaders to restore the water quality in the type of joint effort tried in countless other coastal regions of Florida without success.
Success is what is being seen in Sarasota Bay today.
Key is government and regional water management agencies in the Sarasota Bay region spent $300 million to stem the flow of pollutants, nutrients, and human waste into the bay by upgrading wastewater treatment plants and retrofitting more than 6,000 acres of the watershed with regional stormwater treatment systems, and spent considerable efforts on public information campaigns on the role residents can have in helping to stem individual contributions to pollution in the bay.
The estuary program has just released this year’s results – seagrass coverage in Sarasota Bay increased by 19% between 2022 and 2024, adding 1,912 acres of underwater meadows to support hundreds of thousands of juvenile fish, and create more healthy plants that can help keep the bay clean in their ways.
“This is an encouraging sign,” said David Tomasko, director of the Sarasota Bay Estuary Program. “But we still have a long way to go before we can say the bay is fully healthy.”
History lesson
Sarasota Bay was a key waterway for the Tocobago, Timucuan, and Calusa tribes in the 1500s. They thrived, and large shell mounds are still visible today in places near the waterfront.
Cuban fishermen camped on the same shores from the late 1700s to the mid-1800s, trading in mullet and other seafood.
The decline in water quality, which eventually led to a decline in sea grasses, started with large-scale drainage projects to support the heady rate of homes and neighborhoods that were developed in the late 1800s at Sarasota Bayfront, and spots to the immediate north and south.
Sarasota Bay’s water quality started a serious slide toward unsustainability after World War II when development intensified, leading to significant environmental changes.
Between 1950 and 1990, about 39% of tidal wetlands and 30% of seagrass meadows were lost due to development. Nutrients, including chemicals in fertilizers, were dumped into the bay, either on purpose or due to the lack of environmental repercussions at the time, further stressing water quality.
Eventually, shorelines were altered by seawalls, feeder creeks polluted by businesses and homeowners, and a population boom sent an impossible amount of stormwater runoff and wastewater into the bay, impacting seagrass health lowering meadows from a peak of 13,473 acres in 2016 to just 9,962 acres in 2022 — a loss of more than a quarter of its seagrass beds six years.
That Sarasota Bay’s underwater seagrass meadows are surging back is not only a hopeful sign that efforts to reclaim the health of bays off heavily developed shorelines can work, but it very well may be a blueprint for coastal regions facing similar threats.
The resurgence in Sarasota Bay stands in stark contrast to conditions in other Southwest Florida waterways, where seagrass losses remain a pressing issue.
In Charlotte Harbor, located just south of Sarasota Bay, seagrass acreage declined by 23% between 2018 and 2021.
The harbor has been plagued by excess nutrient pollution from agricultural runoff and urban development, which fuels algae growth that blocks sunlight from reaching seagrass beds.
Despite community-led monitoring programs like Florida Sea Grant’s “Eyes on Seagrass,” reversing these declines has proven difficult.
“Seagrasses are an overarching indicator of the health of an estuary,” said Jennifer Hecker, director of the Coastal and Heartland National Estuary Partnership based in Charlotte Harbor. “When they're declining, that is an indicator that the system is declining in health, and that will, in turn, negatively affect our fisheries, our water quality, and the general ecological health of our coastal waters. So we really need to continue to monitor and track what is going on and get to the root causes.”
Further south, the Caloosahatchee River in Lee County has faced decades of sea grass losses, particularly tape grass. Once covering thousands of acres, tape grass has been decimated by altered freshwater flows and nutrient pollution.
Restoration projects are underway, including sea grass replanting efforts – so precious are the baby shoots that cages are placed over them to prevent grazing by manatees.
For the Caloosahatchee River, a lot is riding on the upcoming completion of the a huge reservoir that will divert water flowing from the highly polluted Lake Okeechobee into manmade wetlands to be cleaned before being return to the river. Hope is that will help.
Estero Bay has seen some of the most severe seagrass declines in Southwest Florida. Only about 4% of its historical seagrass coverage remains due to skyrocketing nitrogen levels that have fueled massive algae blooms that smother seagrass beds.
Estero Bay continues to suffer from nutrient-rich runoff from agricultural lands, septic systems, and aging wastewater infrastructure.
Environmental nonprofits warn that without fast action to reduce pollution and restore natural water flows, Estero Bay’s ecosystem could face irreparable damage.
The challenges facing these neighboring waterways underscore just how significant Sarasota Bay’s recent gains are—and how fragile they remain.
‘Most to gain; most to lose’
Sarasota Bay’s recovery follows the years of collaborative efforts among local governments, environmental organizations, and residents. Now, ongoing monitoring efforts track both the increasing seagrass acreage as well as nitrogen levels and algae concentrations to provide a complete picture of Sarasota Bay’s health.
While there is reason for cautious optimism in Sarasota Bay, Tomasko said more work needs to be done and continued vigilance is necessary to sustain the gains made so far.
“When you live on the waterfront, you have the most to gain — and the most to lose.”
Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.
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